Create cdap-spi with interfaces that abstract StreamEventRecordFormat and related classes

Details

Added interfaces to cdap-spi that abstract StreamEventRecordFormat (and dependent interfaces), so that CDAP users can extend the cdap-spi interfaces.

Rank:

1|hzyy0n:

Description

For CDAP-3387, we first need to create some interfaces in cdap-spi that abstract StreamEventRecordFormat (and dependent interfaces), so that CDAP users can extend the cdap-spi interfaces. We will then have cdap-formats, which contains all of our StreamEventRecordFormat subclasses, depend on cdap-spi.